From: "Wiles, Keith" <keith.wiles@intel.com>
To: Olivier Matz <olivier.matz@6wind.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
"stephen@networkplumber.org" <stephen@networkplumber.org>,
"jerin.jacob@caviumnetworks.com" <jerin.jacob@caviumnetworks.com>
Subject: Re: [dpdk-dev] [PATCH v2] mbuf:using sanity checks do not panic on null mbuf
Date: Tue, 16 Jan 2018 14:19:29 +0000 [thread overview]
Message-ID: <430903DF-0219-4AB6-993C-8DE5915D7CCA@intel.com> (raw)
In-Reply-To: <20180116140429.pyab272uebox2gmn@platinum>
> On Jan 16, 2018, at 8:04 AM, Olivier Matz <olivier.matz@6wind.com> wrote:
>
> On Tue, Jan 09, 2018 at 08:29:28AM -0600, Keith Wiles wrote:
>> The rte_pktmbuf_free() allows for NULL mbuf pointer, but
>> when sanity check is enabled it will panic with null pointer.
>>
>> Signed-off-by: Keith Wiles <keith.wiles@intel.com>
>> ---
>> lib/librte_mbuf/rte_mbuf.c | 10 ++++++++--
>> test/test/test_mbuf.c | 4 +---
>> 2 files changed, 9 insertions(+), 5 deletions(-)
>>
>> diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
>> index 7543662f7..621679c92 100644
>> --- a/lib/librte_mbuf/rte_mbuf.c
>> +++ b/lib/librte_mbuf/rte_mbuf.c
>> @@ -205,8 +205,9 @@ rte_mbuf_sanity_check(const struct rte_mbuf *m, int is_header)
>> const struct rte_mbuf *m_seg;
>> unsigned int nb_segs;
>>
>> - if (m == NULL)
>> - rte_panic("mbuf is NULL\n");
>> + /* Calling with NULL is valid in the API */
>> + if (!m)
>> + return;
>>
>> /* generic checks */
>> if (m->pool == NULL)
>> @@ -243,6 +244,11 @@ rte_pktmbuf_dump(FILE *f, const struct rte_mbuf *m, unsigned dump_len)
>>
>> __rte_mbuf_sanity_check(m, 1);
>>
>> + if (!m) {
>> + fprintf(stderr, "MBUF pointer is NULL\n");
>> + return;
>> + }
>> +
>> fprintf(f, "dump mbuf at %p, iova=%"PRIx64", buf_len=%u\n",
>> m, (uint64_t)m->buf_iova, (unsigned)m->buf_len);
>> fprintf(f, " pkt_len=%"PRIu32", ol_flags=%"PRIx64", nb_segs=%u, "
>> diff --git a/test/test/test_mbuf.c b/test/test/test_mbuf.c
>> index 9e82a20be..146eaf0e5 100644
>> --- a/test/test/test_mbuf.c
>> +++ b/test/test/test_mbuf.c
>> @@ -864,10 +864,8 @@ test_failing_mbuf_sanity_check(struct rte_mempool *pktmbuf_pool)
>>
>> printf("Now checking for error conditions\n");
>>
>> - if (verify_mbuf_check_panics(NULL)) {
>> - printf("Error with NULL mbuf test\n");
>> + if (verify_mbuf_check_panics(NULL) != -1)
>> return -1;
>> - }
>>
>> badbuf = *buf;
>> badbuf.pool = NULL;
>> --
>> 2.14.1
>>
>
> The problem is a panic when rte_pktmbuf_free(NULL) when mbuf debug is enabled,
> right?
>
> A NULL mbuf is only valid in case of a free because it is convenient, but for
> most (all ?) other mbuf functions, the mbuf must not be NULL.
>
> What about this patch instead:
>
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -1413,13 +1413,14 @@ rte_pktmbuf_free_seg(struct rte_mbuf *m)
> * segment is added back into its original mempool.
> *
> * @param m
> - * The packet mbuf to be freed.
> + * The packet mbuf to be freed. If NULL, the function does nothing.
> */
> static inline void rte_pktmbuf_free(struct rte_mbuf *m)
> {
> struct rte_mbuf *m_next;
>
> - __rte_mbuf_sanity_check(m, 1);
> + if (m != NULL)
> + __rte_mbuf_sanity_check(m, 1);
>
> while (m != NULL) {
> m_next = m->next;
Looks good to me I would ack that one. :-)
>
Regards,
Keith
next prev parent reply other threads:[~2018-01-16 14:19 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-08 15:34 [dpdk-dev] [PATCH] " Keith Wiles
2018-01-08 15:39 ` Stephen Hemminger
2018-01-08 15:41 ` Wiles, Keith
2018-01-09 4:39 ` Jerin Jacob
2018-01-09 14:29 ` [dpdk-dev] [PATCH v2] " Keith Wiles
2018-01-16 14:04 ` Olivier Matz
2018-01-16 14:19 ` Wiles, Keith [this message]
2018-01-29 9:39 ` [dpdk-dev] [PATCH v3] mbuf: fix freeing of NULL mbuf when debug enabled Olivier Matz
2018-01-29 15:58 ` Thomas Monjalon
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